Mark Twain was the pen name of Samuel Langhorne Clemens, one of the major authors of American fiction. Twain is also considered the greatest humorist in American literature. Twain's varied works include novels, travel narratives, short stories, sketches, and essays. His writings about the Mississippi River, such as The Adventures of Tom Sawyer, Life on the Mississippi, and Adventures of Huckleberry Finn, have been especially popular among modern readers.